A. A. Wood

Quantum computers demand reliable memory. In a diamond crystal — carbon — information is stored as the orientation of microscopic magnetic needles (spins) at special defects. Reading these arrows with light was inconvenient: optics are bulky for chips. The new method works like developing photographic film.

A tiny diamond hangs in the air, held by an electric field like a speck of dust in a beam of light. Hidden inside are defects — places where a carbon atom is replaced by nitrogen, with a vacancy nearby. These defects behave like little magnets that can be flipped with laser and microwaves.